• A photograph accompanying a report about an avalanche on Mount Everest was captioned: "The avalanche that killed at least 13 sherpas pictured as it sweeps down Mount Everest on 18 April." In fact the photograph did not show that avalanche, but was taken in 2012. A picture agency distributed the photo in error and later sent out a recall notice, which we missed (Sherpas divided over call to block Everest climbs after fatal avalanche, 21 April, page 15).

• The Oxford University college which David Cameron attended, and where he helped organise the ball, was Brasenose, not Balliol ('I'd put £1,000 on Ed to win', 19 April, page 35).

• An article about winners of the Queen's awards for enterprise referred to "artificial preservatives such as ascetic acid". As a reader pointed out, that would be an acid that denied itself base pleasures. We meant the better known acetic acid (Arms firm among Queen's award winners, 21 April, page 20).

• The California University Santa Barbara mentioned in an article (Boots, jeans, even hair governed by the state, 22 April, page 15) is actually the University of California, Santa Barbara.